A trailing beam suspension typically utilizes a beam having a leading end opposite a trailing end. The beam is mounted lengthwise to a hanger at its leading end for swinging movement about an axis transverse to a trailer. The hanger is typically secured to a chassis or frame of the trailer by suitable means such as welding. A suspension unit such as an air bag extends between the trailing end of the beam and the chassis of the trailer. An axle is mounted to the beam transverse to the beam between the leading and trailing ends of the beam.
The above suspension arrangement is referred to as a “trailing beam” suspension because the beam extends rearwardly from its connection to the hanger and accordingly the axle “trails” the pivot point of the suspension system.
In assembling a trailer, there is a need, because of manufacturing tolerances, to provide for some fore and aft adjustment of the axle relative to the hanger to ensure that the axle is orthogonal to a centre line of the trailer. In its simplest form, the adjustment may simply be effected by providing slots in the hangers for receiving a pivot member about which the beam swings to enable fore/aft movement of the pivot member during assembly subsequent to which the components may be secured by friction (bolting), welding or both.
A disadvantage with simply providing a slot to enable movement is that it lacks apparatus for effecting the movement. Accordingly, external force needs to be applied to the beam or the axle to move the pivot member fore and aft. This makes minute adjustments somewhat difficult.
Screw type adjusters which act between the pivot member and the hanger have been proposed, however, such adjusters must be made quite robust and as well, the hanger suitably braced, for such to be effective. In any case, the screw generally cannot be relied upon to control fore/aft movement and accordingly, absent welding the components in place after adjustment, there is a risk of movement of the pivot member in the slot and ensuing misalignment.
Its is an object of the present invention to provide a trailing beam hanger and alignment apparatus which overcomes at least some of the problems associated with prior devices.